The present disclosure relates to a high voltage direct current (HVDC) transmission system, and more particularly, to an HVDC transmission system that may damp oscillation generated in the HVDC transmission system, and a control method thereof.
High voltage direct current (HVDC) transmission indicates a power transmission method of converting, by a transmission site, AC power produced at a power station into DC power to transmit the DC power and then re-converting, by a reception site, AC power into DC to supply AC power.
An HVDC system is applied to submarine cable power transmission, large-amount long-distance power transmission, interconnection between AC systems, etc. Also, the HVDC transmission system enables different frequency system interconnection and asynchronism interconnection.
The transmission site converts the AC power into the DC power. That is, since transmitting the AC power by using a submarine cable is significantly dangerous, the transmission site converts the AC power into the DC power to transmit the DC power to the reception site.
The HVDC transmission system may have mechanical, torsional oscillation according to the operation of a three-phase AC generator in the HVDC system.
When the low-frequency oscillation including the mechanical, torsional oscillation is maintained or amplified without disappearing in the HVDC, it may have a serious effect on the stability of a power system in the HVDC system.
Thus, there is a need to damp low-frequency oscillation generated in the HVDC transmission system.